1. Field of the Invention
The present invention relates to a production process of a chemical amplification-type positive or negative resist composition for use in the process of producing a semiconductor such as IC, in the production of a circuit board for liquid crystal, thermal head and the like, or in other photofabrication processes. More specifically, the present invention relates to a production process of a chemical amplification-type positive or negative resist composition suitable for exposure using a light source of emitting a far ultraviolet ray or the like of 250 nm or less.
2. Description of the Related Art
The chemical amplification-type positive resist composition is a pattern forming material which is sparingly soluble or insoluble in a developer immediately after the film formation on a substrate but produces an acid in the exposed area upon irradiation with radiation such as far ultraviolet ray and through a reaction using this acid as the catalyst, increases the solubility of the actinic radiation-irradiated area in a developer, thereby forming a pattern on the substrate. Also, the chemical amplification-type negative resist composition is a pattern forming material which is easily soluble in a developer immediately after the film formation on a substrate but produces an acid in the exposed area upon irradiation with radiation such as far ultraviolet ray and through a reaction using this acid as the catalyst, decreases the solubility of the actinic radiation-irradiated area in a developer, thereby forming a pattern on the substrate.
As described, for example, in JP-A-2002-296779 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”), the chemical amplification-type resist composition for the processing using a light source (radiation source) such as KrF excimer laser, ArF excimer laser, F2 excimer laser, EUV (extreme ultraviolet light) and EB (electron beam) generally comprises a resin component, an acid generator component capable of generating an acid upon exposure, and an organic solvent capable of dissolving these components.
Such a chemical amplification-type resist composition is required to give a resist pattern with high resolution, high sensitivity and good profile.
In recent years, a high-resolution resist pattern of 0.11 microns or less is demanded, as a result, in addition to the above-described properties, the improvement of defect (surface defect) of the resist pattern after development is required more strongly than ever.
This defect indicates troubles in general, for example, detected by a surface defect inspection apparatus (“KLA”, trade name) manufactured by KLA-Tencor Corp. when the resist pattern after development is observed from right above. Examples of the trouble include scum after development, bubble, dust and bridge between resist patterns.
In order to improve such a defect, the efforts heretofore mainly attempted are centered on the resist composition, such as resin component, acid generator component and solvent component of the resist composition [JP-A-2001-56556].
Furthermore, generation of a fine particle during storage of the resist solution (resist composition in the solution state), that is, the foreign matter aging property (the property that a solid-state foreign matter is generated in the resist composition while the resist composition is stored; storage stability) of the resist solution, is also a problem and improvement thereof is demanded.
In order to improve this foreign matter aging property, similarly to the above, efforts centered on the resist composition have been attempted [JP-A-2001-22072].
However, the effects of the techniques described in JP-A-2001-56556 and JP-A-2001-22072 are not yet sufficient.
In addition, the generation of a fine particle may give rise to the above-described defect, and improvement of the foreign matter aging property is strongly demanded also from the standpoint of improving the defect.
However, a method capable of sufficiently improving the defect of resist pattern after development and the storage stability has been heretofore not known.
Meanwhile, JP-A-2002-62667 has proposed a production process of a resist composition, where the amount of a fine particle in the resist composition circulating in the line is reduced by passing the resist composition through a filter.
As described in JP-A-2002-62667, in the production of a resist composition, it is known to produce a resist composition and pass the composition through a filter, but even such a process is not enough to satisfactorily improve the defect of resist pattern after development and the storage stability.
Also, JP-A-2001-350266 has proposed a production process of a resist composition, where the resist composition is passed through a filter having a positive zeta potential. However, when the resist composition is treated by the method described in JP-A-2001-350266, the constitution of the composition is sometimes changed. This change in the constitution disadvantageously causes change in the sensitivity of the resist composition or in the resist pattern size.
JP-A-2001-350266 has proposed a production process of a resist composition, where the resist composition is passed through a filter having a negative zeta potential. However, as for the defect of the resist pattern, in the case of forming the recently demanded fine resist pattern such as resist pattern of 110 nm or less by using a KrF excimer laser or a light source developed thereafter, such as KrF excimer laser, ArF excimer laser, F2 excimer laser, EUV and EB, the problem of defect becomes severer and the above-described production process is not enough to solve the problem.
JP-A-2004-212975 discloses a technique of passing the resist composition through a filter comprising a membrane having a specific zeta potential so as to provide a resist composition ensuring that generation of a defect in the resist pattern after development can be suppressed.
That is, the defect such as fine scum or microbridge after development becomes a severer problem along with miniaturization of the pattern, and it is a very important concern to suppress the defect. However, none of those conventional techniques is successful in satisfactorily solving this problem.
Also, JP-A-10-232492 discloses a technique where in the preparation of a resist for i-line, the raw materials are mixed each in the form of a solution to enhance the charging accuracy and thereby enhance the dimensional accuracy of the resist pattern obtained from the composition.
JP-T-10-512970 (the term “JP-T” as used herein means a “published Japanese translation of a PCT patent application”) discloses a method of, in the preparation of a resist, using a novolak resin in which the metal ion amount is reduced with the use of an ion exchange resin.
JP-T-2004-523806 discloses a technique of reducing the metal amount and enhancing the film-forming property by filtering the resin solution.
JP-A-2004-326092 discloses, in the preparation of a resist, performing a treatment of bringing a resin into contact with activated carbon.
JP-A-2003-330202 discloses a method of filtering a resin solution so as to prevent the resist from deterioration with time.